The Rodent Peril-"they mostly come at night......mostly."*

We have a problem with bats.

Yes, I know.  Bats are not Rodentia, being members instead of the class Chiroptera.  But my excuse is that in German they are called "fliegermaus" or "flying mouse".  And if you get close enough to check for rodent like incisor teeth:

Well, by now it is too late to remind you that bats are notorious for being carriers of rabies.

Anyway, while I entirely approve of the local bats eating mosquitoes I take great exception with them using my entryway as a latrine.  Yech!  Bat excreta infested with rabies virus all over the Welcome mat, and no doubt tracked in as well.

So the Bat Wars began.

At first we thought they were daytime snoozing in some small cracks between the house and the overhang.  I carefully pushed wire screening into all such nooks and crannies.  No decrease in bat scat.  Thus it became apparent that they were simply hanging on the rafters and relieving themselves, like beer sodden college students wandering home after a binge.

First I nailed up plastic sheeting, screening off their favorite haunts.  This worked, but it looked kind of shabby, and created enclosed spaces that I suspected would become a happy lair for some other nasty life form.  So down it came.

Next up....fabric softener sheets.  Yes, we had it on good authority that these were a serious annoyance to our Chiroptera pals.  I put up a half dozen wire pouches full of the stuff.  The porch smelled great.  The bat excreta increased.

I had some wasp killer spray.  A liberal application of this did have a temporary impact, probably by reducing the available bat snack bugs.  But it seemed an expensive and environmentally unfriendly solution.

We also had deer repellent spray.  Nasty stuff, lots of ammonia in it.  Impact: modest, and every time I sprayed it upwards I got a good whiff.

Bags of moth balls, now there's an old time favorite.  Total myth, for bat deterrence they did nothing.

Finally I was alerted to this site:  http://batcow.org/  It actually had some useful info, leading me to create this:

These are sheets of aluminum foil.  I put a strip of duct tape across the top so staples would hold better.  Then I cut them into delicate fronds that wave in the slightest breeze.  Since bats navigate by sonar this should send all manner of disturbing echos back at them.  The technology is very similar to "chaff", foil strips dropped by aircraft to confuse radar.

So far it seems to be working well.  Which is probably a good thing.  My next approach was going to be more extreme.  I have somewhere in the basement an old motorized disco ball.  I figured I could wire it up to a motion sensor, add a couple of laser pointers and really mess with their squeaky little biological GPS systems.

Wise Spouse points out that this might lead the neighbors to conclude that somebody odd lives at our address.  And she may be right.  I suppose there are still a few for whom this is merely a sneaking suspicion, and there is at present no need to confirm it for them.
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*Yes, another quote from Aliens, one of my favorite movies:

Newt: We'd better get back, 'cause it'll be dark soon, and they mostly come at night... mostly.